The present invention relates generally to lipstick containers, and more particularly to lipstick containers having mechanical mechanisms for manipulating their associate lipstick masses longitudinally within the containers between extended and retracted positions.
Lipstick containers having mechanisms for manipulating their associated lipstick masses are well-known in the art. The prior art containers generally have a main inner body member having a finger engaging knob or base portion at one end thereof and a tubular sleeve portion at the other end thereof. Extending longitudinally in the tubular sleeve portion are a pair of diametrically opposed elongated slots with locking portions at their terminal ends.
Mounted within the tubular sleeve portion is a cup element adapted to receive the lipstick mass and having a pair of diametrically opposed, outwardly extending posts captured in the pair of slots in the tubular sleeve. The posts are also captured in a pair of helical or spiral grooves formed in the inner wall of an outer sleeve which surrounds the tubular sleeve of the inner body member. The inner body member and the outer sleeve are mechanically retained to one another at their upper ends by a conventional lip and groove arrangement which permits relative rotational movement therebetween.
In operation, relative rotation between the inner body member and the outer sleeve foces the captured posts of the cup member to follow both the longitudinal slots of the inner body member and the helical grooves of the outer sleeve thereby moving the cup element longitudinally in the inner body member, alternatively, between its retracted locked position completely within the inner body member and its protracted locked position extending partially outside the inner body member. In its retracted locked position, the posts of the cup member are located within the lower locking portions (adjacent the knob or base portion) of the longitudinal slots; the cup being thereby inhibited from longitudinal movement during transportation and handling of the lipstick container. In its protracted locked position, inadvertent downward movement of the cup is inhibited during both the loading of the lipstick mass into the container during the assembly process and the application of associated lipstick onto a user's lips.
One of the problems which has been encountered in the use and manufacture of such containers is wide, undesirable variations in the swivel torque required to control the relative rotation of the inner body member and the outer sleeve to drive the cup element between the retracted and protracted positions.
Swivel torque for lipstick container is generally measured in inch-ounces with the ideal range of acceptability being two (2) to six (6) inch-ounces. To achieve this range in the prior art lipstick containers, a variety of methods have been used including manufacturing the cup element to have an outer diameter slightly larger than the inner diameter of the main body member whereby the cup member tends to resist longitudinal movement within the inner body member. In practice, due to manufacturing inaccuracies, such as encountering nonuniform inner diameters of the main body member as the cup element moves axially therethrough, the swivel torque found in the prior art devices tends to range from one (1) to thirteen (13) inch-ounces and can vary dramatically over the stroke of the cup element between its retracted and protracted positions. Oftentimes, the containers with swivel torques at the upper end of this range are nearly inoperable and must be rejected and discarded as having unacceptably high swivel torques. Other prior art methods for controlling swivel torque include providing an interference fit between the outer sleeve and the inner body member either along the entire adjacent peripheries thereof or solely at the upper ends thereof. However, these methods have proved equally unsuccessful for producing mass production containers which fall within the ideal range of swivel torque acceptability.
Another undesirable feature of the prior art designs, is the presence of unwanted longitudinal movement or "shuck" between the inner body member and the outer sleeve. Such "shuck" can be attributed to manufacturing tolerances and the type of connection (lip and groove) utilized between the inner body member and the outer sleeve.
The present invention is designed to overcome the above-noted limitations, and toward this end, it contemplates the provision of a novel lipstick container which can be manufactured on a high volume basis and consistently fall within the ideal range of swivel torque.
It is an object to provide such a lipstick container which has a uniform swivel torque throughout the length of its stroke thereby creating an ultrasmooth operating mechanism.
Still another object is to provide such a lipstick container which eliminates relative longitudinal movement or "shuck" between its inner body member and outer sleeve.
A further object is to provide such a container which may be readily fabricated and will enjoy long life in operation.